(1) Field of the Invention
The present invention relates to a resinous composition having excellent toughness, flexibility, heat resistance and moldability.
(2) Description of the Prior Art
Recently, a molding composition which comprises a polyamide and a various polyolefin has been investigated in order to enhance impact strength of polyamide in the absolute dried condition and in the cold condition and to improve heat resistance, especially rigidity and creep resistance of polyolefin at higher circumambient temperatures. However, it is generally difficult to obtain an intimate composition comprising a polyamide and a polyolefin by melt-blending of both components using such as extruder, on account of that both polarity and reactivity is so different between a polyamide and a polyolefin that these both components have poor compatibility each other. In order to conquer this disadvantage and obtain an intimate composition comprising a polyamide and a polyolefin, various methods and compositions have been proposed. For example, U.S. Pat. Nos. 3,845,163 and 4,174,358 disclose compositions comprising polyamide and polyolefin modified with .alpha.,.beta.-unsaturated carboxylic acid derivatives which can react chemically with polyamide. The compositions disclosed in the above-mentioned prior arts show fine morphology and an enhancement of impact strength of polyamide can be achieved because of a high reactivity of the modified polyolefin.
But on the other hand, there appears distinct disadvantage owing to reaction between the polyamide and the modified polyolefin, that is, as a result of said reaction, fluidity of the composition at injection molding is deteriorated and the surface appearance of the molded articles becomes poor on account of local increase of viscosity.
It has now been found that the resinous composition having both excellent physical properties in respect to toughness, flexibility and heat resistance and good moldability can be provided according to a composition comprising a polyamide and a polyolefin modified with functional groups which cannot substantially react with the terminal amino groups or amide groups in the main chain of the polyamide but can enhance compatibility to the polyamide.